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1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016 Facebook
4 */
5
6#include <linux/bpf.h>
7
8#include "disasm.h"
9
10#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
11static const char * const func_id_str[] = {
12 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
13};
14#undef __BPF_FUNC_STR_FN
15
16static const char *__func_get_name(const struct bpf_insn_cbs *cbs,
17 const struct bpf_insn *insn,
18 char *buff, size_t len)
19{
20 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
21
22 if (insn->src_reg != BPF_PSEUDO_CALL &&
23 insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID &&
24 func_id_str[insn->imm])
25 return func_id_str[insn->imm];
26
27 if (cbs && cbs->cb_call)
28 return cbs->cb_call(cbs->private_data, insn);
29
30 if (insn->src_reg == BPF_PSEUDO_CALL)
31 snprintf(buff, len, "%+d", insn->imm);
32
33 return buff;
34}
35
36static const char *__func_imm_name(const struct bpf_insn_cbs *cbs,
37 const struct bpf_insn *insn,
38 u64 full_imm, char *buff, size_t len)
39{
40 if (cbs && cbs->cb_imm)
41 return cbs->cb_imm(cbs->private_data, insn, full_imm);
42
43 snprintf(buff, len, "0x%llx", (unsigned long long)full_imm);
44 return buff;
45}
46
47const char *func_id_name(int id)
48{
49 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
50 return func_id_str[id];
51 else
52 return "unknown";
53}
54
55const char *const bpf_class_string[8] = {
56 [BPF_LD] = "ld",
57 [BPF_LDX] = "ldx",
58 [BPF_ST] = "st",
59 [BPF_STX] = "stx",
60 [BPF_ALU] = "alu",
61 [BPF_JMP] = "jmp",
62 [BPF_JMP32] = "jmp32",
63 [BPF_ALU64] = "alu64",
64};
65
66const char *const bpf_alu_string[16] = {
67 [BPF_ADD >> 4] = "+=",
68 [BPF_SUB >> 4] = "-=",
69 [BPF_MUL >> 4] = "*=",
70 [BPF_DIV >> 4] = "/=",
71 [BPF_OR >> 4] = "|=",
72 [BPF_AND >> 4] = "&=",
73 [BPF_LSH >> 4] = "<<=",
74 [BPF_RSH >> 4] = ">>=",
75 [BPF_NEG >> 4] = "neg",
76 [BPF_MOD >> 4] = "%=",
77 [BPF_XOR >> 4] = "^=",
78 [BPF_MOV >> 4] = "=",
79 [BPF_ARSH >> 4] = "s>>=",
80 [BPF_END >> 4] = "endian",
81};
82
83static const char *const bpf_ldst_string[] = {
84 [BPF_W >> 3] = "u32",
85 [BPF_H >> 3] = "u16",
86 [BPF_B >> 3] = "u8",
87 [BPF_DW >> 3] = "u64",
88};
89
90static const char *const bpf_jmp_string[16] = {
91 [BPF_JA >> 4] = "jmp",
92 [BPF_JEQ >> 4] = "==",
93 [BPF_JGT >> 4] = ">",
94 [BPF_JLT >> 4] = "<",
95 [BPF_JGE >> 4] = ">=",
96 [BPF_JLE >> 4] = "<=",
97 [BPF_JSET >> 4] = "&",
98 [BPF_JNE >> 4] = "!=",
99 [BPF_JSGT >> 4] = "s>",
100 [BPF_JSLT >> 4] = "s<",
101 [BPF_JSGE >> 4] = "s>=",
102 [BPF_JSLE >> 4] = "s<=",
103 [BPF_CALL >> 4] = "call",
104 [BPF_EXIT >> 4] = "exit",
105};
106
107static void print_bpf_end_insn(bpf_insn_print_t verbose,
108 void *private_data,
109 const struct bpf_insn *insn)
110{
111 verbose(private_data, "(%02x) r%d = %s%d r%d\n",
112 insn->code, insn->dst_reg,
113 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
114 insn->imm, insn->dst_reg);
115}
116
117void print_bpf_insn(const struct bpf_insn_cbs *cbs,
118 const struct bpf_insn *insn,
119 bool allow_ptr_leaks)
120{
121 const bpf_insn_print_t verbose = cbs->cb_print;
122 u8 class = BPF_CLASS(insn->code);
123
124 if (class == BPF_ALU || class == BPF_ALU64) {
125 if (BPF_OP(insn->code) == BPF_END) {
126 if (class == BPF_ALU64)
127 verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
128 else
129 print_bpf_end_insn(verbose, cbs->private_data, insn);
130 } else if (BPF_OP(insn->code) == BPF_NEG) {
131 verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
132 insn->code, class == BPF_ALU ? 'w' : 'r',
133 insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
134 insn->dst_reg);
135 } else if (BPF_SRC(insn->code) == BPF_X) {
136 verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
137 insn->code, class == BPF_ALU ? 'w' : 'r',
138 insn->dst_reg,
139 bpf_alu_string[BPF_OP(insn->code) >> 4],
140 class == BPF_ALU ? 'w' : 'r',
141 insn->src_reg);
142 } else {
143 verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
144 insn->code, class == BPF_ALU ? 'w' : 'r',
145 insn->dst_reg,
146 bpf_alu_string[BPF_OP(insn->code) >> 4],
147 insn->imm);
148 }
149 } else if (class == BPF_STX) {
150 if (BPF_MODE(insn->code) == BPF_MEM)
151 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
152 insn->code,
153 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
154 insn->dst_reg,
155 insn->off, insn->src_reg);
156 else if (BPF_MODE(insn->code) == BPF_XADD)
157 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) += r%d\n",
158 insn->code,
159 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
160 insn->dst_reg, insn->off,
161 insn->src_reg);
162 else
163 verbose(cbs->private_data, "BUG_%02x\n", insn->code);
164 } else if (class == BPF_ST) {
165 if (BPF_MODE(insn->code) != BPF_MEM) {
166 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
167 return;
168 }
169 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
170 insn->code,
171 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
172 insn->dst_reg,
173 insn->off, insn->imm);
174 } else if (class == BPF_LDX) {
175 if (BPF_MODE(insn->code) != BPF_MEM) {
176 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
177 return;
178 }
179 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
180 insn->code, insn->dst_reg,
181 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
182 insn->src_reg, insn->off);
183 } else if (class == BPF_LD) {
184 if (BPF_MODE(insn->code) == BPF_ABS) {
185 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
186 insn->code,
187 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
188 insn->imm);
189 } else if (BPF_MODE(insn->code) == BPF_IND) {
190 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
191 insn->code,
192 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
193 insn->src_reg, insn->imm);
194 } else if (BPF_MODE(insn->code) == BPF_IMM &&
195 BPF_SIZE(insn->code) == BPF_DW) {
196 /* At this point, we already made sure that the second
197 * part of the ldimm64 insn is accessible.
198 */
199 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
200 bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
201 insn->src_reg == BPF_PSEUDO_MAP_VALUE;
202 char tmp[64];
203
204 if (is_ptr && !allow_ptr_leaks)
205 imm = 0;
206
207 verbose(cbs->private_data, "(%02x) r%d = %s\n",
208 insn->code, insn->dst_reg,
209 __func_imm_name(cbs, insn, imm,
210 tmp, sizeof(tmp)));
211 } else {
212 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
213 return;
214 }
215 } else if (class == BPF_JMP32 || class == BPF_JMP) {
216 u8 opcode = BPF_OP(insn->code);
217
218 if (opcode == BPF_CALL) {
219 char tmp[64];
220
221 if (insn->src_reg == BPF_PSEUDO_CALL) {
222 verbose(cbs->private_data, "(%02x) call pc%s\n",
223 insn->code,
224 __func_get_name(cbs, insn,
225 tmp, sizeof(tmp)));
226 } else {
227 strcpy(tmp, "unknown");
228 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
229 __func_get_name(cbs, insn,
230 tmp, sizeof(tmp)),
231 insn->imm);
232 }
233 } else if (insn->code == (BPF_JMP | BPF_JA)) {
234 verbose(cbs->private_data, "(%02x) goto pc%+d\n",
235 insn->code, insn->off);
236 } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
237 verbose(cbs->private_data, "(%02x) exit\n", insn->code);
238 } else if (BPF_SRC(insn->code) == BPF_X) {
239 verbose(cbs->private_data,
240 "(%02x) if %c%d %s %c%d goto pc%+d\n",
241 insn->code, class == BPF_JMP32 ? 'w' : 'r',
242 insn->dst_reg,
243 bpf_jmp_string[BPF_OP(insn->code) >> 4],
244 class == BPF_JMP32 ? 'w' : 'r',
245 insn->src_reg, insn->off);
246 } else {
247 verbose(cbs->private_data,
248 "(%02x) if %c%d %s 0x%x goto pc%+d\n",
249 insn->code, class == BPF_JMP32 ? 'w' : 'r',
250 insn->dst_reg,
251 bpf_jmp_string[BPF_OP(insn->code) >> 4],
252 insn->imm, insn->off);
253 }
254 } else {
255 verbose(cbs->private_data, "(%02x) %s\n",
256 insn->code, bpf_class_string[class]);
257 }
258}